hi,i have a Dell D610 laptop, it starts up only till the F2 F12 boot screen then goes blank/grey?i have used the cd for diagnostic testing and all works fine and the screen works too?please can someone help with what this could be?thank you very much

no error messages blank screenthe diagnostic test i did was for boot startup and video then i did the quick test and everything seemed ok.it has the 9 in a lock key lit which some say is just the numlock key lit up but even when i take it off it goes back on again when computer attempts to start...